1. Field
Aspects of embodiments of the present invention relate to a secondary battery, and more particularly, to a secondary battery having a reduced thickness.
2. Description of the Related Art
As representative rechargeable secondary batteries, lithium (Li) secondary batteries have a high operational voltage and energy density per unit weight as compared with nickel-cadmium (Ni—Cd) or nickel-hydrogen (Ni-MH) secondary batteries. Hence, their uses have been increased.
As the use of portable electronic devices increases, the use of secondary batteries increases. Studies for reducing the size and thickness of secondary batteries have been conducted based on user's demands.
Currently, a memory unit for storing information and a process unit for processing information are embedded into a smart card. To this end, a technology for embedding a battery into a smart card has been developed.
In Japanese Patent Laid-Open Publication No. 2005-10859 (published on Jan. 13, 2005), there has been disclosed a thin-film integrated circuit (IC) card into which a secondary battery such as a capacitor or lithium secondary battery, sealed by a case, is embedded not to overlap with an IC module.
A need exists for the thickness of secondary batteries to be decreased so that smart cards may be manufactured to have a size suitable for international standards.